Rebuilt my carb this weekend. It's an Edelbrock 600. It had been running horrendously rich, now it just runs a little rich. No big deal there, I'll just change out the rods and springs until it acts right. Been there before. Where I have not been before though, is the Duraspark. I know a thing or two about Chevy engines, but this is my first Ford. What I'm looking for is a little bit of background. Maybe your experience can tell me which direction I might need to go to chase these two little problems. First, got a problem at WOT. After the carb rebuild, good God it woke up! It screams, slams me back in the seat and does everything it should do up to a point. Once the RPMs are really up it acts almost like it has a rev limiter. Power goes away and it pops and chokes. (Sorry I don't have a tach so I don't know exactly where this happens, but it's nothing too insane.) So, first thing I wonder, does the Duraspark HAVE a limiter? Or is it perhaps not capable of handling those RPMs in stock form? Or would you think my timing is off? Maybe it's advancing too much... Could it be overly restrictive exhaust? I'm running stock manifolds, but everything after that is upgraded. Maybe it's still the carb, but my gut tells me it's ignition. Second problem, low-throttle cruise isn't always so smooth. I thought carb at first, but I can't seem to tune that out so I'm starting to think about other things. First I thought the previous super-rich condition must have fouled the plugs, but it runs so nice when I give it a little gas... Maybe I should replace those plugs just on principle, but they look like such a bitch to get to. ('Course, that might be an indication that they haven't been changed in a long time...) So what do y'all think? Is my ignition system sick? I hate playing the game of throwing parts at something 'til the problem stops, but that's my next step; start replacing ignition components... Thanks!
It could be starving for fuel at the higher rpms. Just a thought. I'd change out those plugs to rule those out though (along with the distributor cap, wires if they look old). If working on a car was easy, women and children would be doing it. (j/k ladies)
Yeah, think I'll do that just to be sure. Can't hurt anything except my knuckles. Surely putting a V8 in these cars was an afterthought on Ford's part... I'll do the cap too, it looks pretty old.
What is your current engine setup? I have that edelbrock 600 and it runs great up to when I really need it. I am thinking my engine needs more carb. My edelbrock has the richest springs, rods, and jets that the kit came with, and it still starves when I really get on it. After I put in my new cam, it will likely just be worse. Getting ready to rebuild a 750 Holley Double Pumper and see if that fixes the carb end of things.
Did that already when I rebuilt the carb. Sure needed it too. Actually after doing some reading, I am very, very tempted to convert this to HEI. Couldn't get simpler and a lot of people seem to have done this with great results. Maybe that's just the Chevy devil on my shoulder...
If you could afford it an MSD or Mallory setup will NOT hurt. Get more and stronger spark to that engine. I upgraded to just a Pertronix on a new O'Reilly stock replacement distributor and Accel Super Stock coil. I was able to increase my plug gap to around .045 and still get a nice healthy spark, plus without points, it will start right up (no more of that turning over for 10 seconds while pumping on the gas pedal!) By the way, post some more pics of that car. That paint job looks an awful lot like what I was planning to do this winter...
I used a Crane Cams ignition conversion on mine. Pretty simple swap too! It made a world of difference! When you change the cap/wires/plugs make sure to change the rotor. Good Luck!
Well I already found part of the problem, or at least it's not helping... Very sloppy wiring on this ignition setup. Stuff twisted together and barely clinging to a post on the solenoid, tape and cable ties everywhere... Speaker wire?! ...I'm gonna clean all that up tonight, replace some of it and see if that helps. I've still made up my mind to upgrade the ignition though. Too easy and too cheap not to do it.
Well I think I fixed it. Runs a lot better now after I cleaned up that wiring and reduced the number of connections. I know I must be getting a better connection where the Duraspark box is wired to the solenoid, as it's now done with a crimp connector instead of just twisted around the terminal without even a nut on it. This must have been just a quick hack to get it running after some problem, because the rest of the work done on this car reflects a lot more care. But anyway, I'm still replacing the whole ignition system. I found a deal too good to pass up on an HEI conversion, and that gets me a brand new cap, coil, rotor, module, whole new distributor with new bushings, etc. and will take out all the guesswork. I couldn't have reconditioned the Duraspark for less, and it will be nice and clean too! Full report with pics coming as soon as I get it installed...
The high rpm fall off sounds like too much advance. I picked up an adjustable vacuum adv canister from AA for 12 bux and put it on my DS. I put tons of advance in at the balancer, but then cut the vacuum advance back until it lost the top end sputter. I have 20 or so advance on the balancer, then turned the adjusting screw out on the can until it smoothed... half turn at a time. I am backed out 5 turns of a possible 6 on the can. It lists at Advance for a 68 Fairlane 302 2v. Is about 12 bux and change. Edit: Duh! Sorry. This thread is old... Missed that. You already got the HEI in don't you!
Yeah, too late to keep me from dabbling in the dark side... Still, lesson learned. Maybe next time I run into a tired Duraspark I might try to save it. Thanks! They're new take-off Mustang GT wheels, '06 or '07 I believe. Tires are stock for the 'Stang, Pirelli PZero Nero 235/55/ZR17, and I did use adapters. I got a good deal on them with almost no miles, else I would have chosen a slightly smaller sidewall and maybe a little wider tread on the tire, but these are a good fit anyway I think. Got some other pics here.
